Page 171 - The Miracle in the Cell Membrane

The picture above shows absorption of alcohol molecules by brain
cell membranes. Alcohol molecules close brain cells down one by one
by preventing the passage of nerve signals.

tems, they enter the brain very slow ly, or not at all. These
may be large mol e cu les such as pro teins or small ones like
sodi um. Glucose—the brain's main source of the ener gy it
needs—and the amino acids that it can not pro duce itself,
are not sol u ble in fat. Therefore, these sub stan ces are car -
ried through the cell mem brane by par tic u lar trans port ers.
The human brain uses more than 120 grams of glu cose a
day. But since it can not store more than 2 grams, glu cose
must be con stant ly pass through the bar ri er.
In the light of this need, a great many trans port ers in
every endo the li um cell allow it to absorb large quan ti ties of
glu cose from the blood. The glu cose trans port sys tem is the
body's hard est-work ing trans port sys tem. The cell itself

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